What is deep brain stimulation (DBS)?
Deep brain stimulation (DBS) is a surgical option for patients with Parkinson's disease (PD), essential tremor (ET) and dystonia. Other possible applications for DBS include treatment for epilepsy and severe depression.
During DBS surgery, electrodes are implanted within the brain to deliver electrical impulses. The stimulation offers patients relief from the tremors, rigidity, slowness of movement and stiffness associated with PD, the tremor associated with ET (also called familial tremor). DBS also offers relief from the often painful muscle contractions associated with dystonia and may also help with balance problems. The stimulation can be adjusted as a patient's condition changes over time.
DBS is a new and improved variation of two previous surgeries, a thalomotomy and a pallidotomy. These surgeries involved destroying small parts of the brain within structures called the thalamus and the globus pallidus (GPi). The surgeries are still being done, but much less often, as DBS no longer makes it necessary to destroy even small parts of the brain.
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How does DBS work?
An electrode implanted in the brain emits pulses of energy to block the abnormal activity in the brain which causes the symptoms. The success of DBS surgery is directly related to:
- Choosing the right candidates for the surgery
- Finding the specific area in the brain for stimulation
- Finding the right settings on the stimulator after surgery
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Who is a candidate for DBS surgery?
Candidates for DBS surgery are patients:
- With PD symptoms that are causing a decline in quality of life
- Who have had an adequate and reasonable trial of medications (includes ET, dystonia and PD)
- Who still respond to medications but are bothered by side effects
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How is DBS surgery done?
It is important to note that surgical techniques can vary among centers and surgeons. The surgical method described here is just one way to perform the procedure.
DBS involves implanting a thin wire, or lead, containing four electrode contacts into a specific target area in the brain. The target area is called the subthalamic nucleus (STN) for PD, the thalamus for ET and the GPi for dystonia and PD. The lead extends through a small opening in the skull and is connected to an extension wire. The extension wire is connected to a pulse generator or “pacemaker” that is implanted under the skin in the chest. This generator is programmable from the outside and programming is done after all of the surgeries are completed.
The surgeon is aided by computerized brain-mapping technology to find the precise location in the brain where nerve signals generate the tremors and other symptoms. Highly sophisticated imaging and recording equipment are used to map both the physical structure and the functioning of the brain.
The patient is awake during surgery to allow the surgical team to assess brain functions. When the surgeon makes the small opening in the skull, a local anesthetic is used to numb the area. While the electrode is being advanced through the brain, the patient does not feel any pain because of the unique nature of the human brain and its inability to generate pain signals.
Most patients are in the hospital for two or three days for implantation of the electrodes. At a later date, usually within a week, the pacemaker(s) is implanted below the collarbone and is done as a same-day surgery procedure. The patient is placed under general anesthesia for this procedure. The stimulators are turned on for the first time within a few weeks after implantation.
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What happens after DBS surgery?
A series of adjustments in the electrical pulse will be made over the next weeks or months. It is necessary for patients to be able to travel to a location where the stimulation of their implanted pacemakers can be adjusted following surgery. The first few follow-up visits should be to the place where the surgery was performed. Subsequent electrical programming can take place at another medical facility if a specialist with the knowledge and equipment is there.
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How effective is DBS?
While results vary from patient to patient, in properly selected patients DBS is remarkably safe and effective, although not without risk. Beneficial effects have been demonstrated to last for several years. Patients with ET may experience an 80 percent to 100 percent reduction in their tremors.
Patients with PD who initially responded well to medications but over time have developed side effects may experience a 60 percent to 80 percent improvement in symptoms such as tremor and slowness of movement. On average, patients report a 50 percent improvement in their walking and balance. Similarly, patients with involuntary movements (dyskinesia) due to their medications experience a greater than 80 percent reduction in their involuntary movements. Most patients are able to significantly reduce their medications following deep brain stimulation.
An important indicator of the effectiveness of any treatment for people with PD, in particular, is the duration of "on-time" without dyskinesia. This means the patient is mobile and can perform everyday tasks without experiencing the involuntary movements. On average, DBS doubles the amount of "on-time" without dyskinesia.
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What risks are associated with DBS?
As with any surgery, the procedure is not risk free. There is about a 2 percent to 3 percent chance of brain hemorrhage that may be of no significance or may cause paralysis, stroke, speech impairment or other major problems. This means that for every 100 patients who undergo surgery, two or three will experience a permanent or severe complication. However, this also means that most patients will have no serious complications.
There is a 15 percent chance of a minor or temporary problem. Rarely, infections can occur. While treatment of infection may require removal of the electrode, the infections themselves have not caused lasting damage. The device can be implanted again after the infection clears.
The electrode that is implanted in the brain and the electrical systems that provide stimulation are generally very well tolerated with no significant changes in brain tissue around the electrodes.
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Who can be evaluated for DBS?
Patients with Parkinson's disease, essential tremor and dystonia with movement-related symptoms that cannot be controlled by medications can be evaluated as possible candidates for DBS. In addition, patients who experience intolerable side effects from medication may also be candidates. New indications for DBS are being investigated and include epilepsy, Tourette’s syndrome, depression and chronic pain syndromes.
DBS has been successful in treating patients as young as 13 years old. In general, surgery is performed on patients under 75 years old; this is not a firm cutoff age, however. Each patient must be assessed individually in regard to his or her stamina and overall health.
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Has DBS been approved by the Food and Drug Administration?
Yes. In January 2002, the FDA approved deep brain stimulation for the treatment of Parkinson's disease. DBS was approved for the treatment of essential tremor in 1997.
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Does Medicare cover DBS?
This procedure is covered by Medicare for the treatment of Parkinson’s disease and essential tremor. In Wisconsin, Medicare also covers DBS for dystonia. Outside of Medicare, most insurance companies are also covering the costs of DBS surgery. To determine if your insurance policy covers all or a portion of the cost, you need to contact your benefit representative directly. If you need help with this, please contact us.
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How do I contact Froedtert & The Medical College of Wisconsin for more information?
To speak to someone about our program, or to make an appointment for an initial evaluation with a movement disorders neurologist, please call 414-805-3666 or 800-272-3666.
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